Sewing machine

ABSTRACT

A sewing machine which in the preferred embodiment includes a hinged stretch bar regulatably biased for applying pressure against a fabric being fed through centralizing slots in a vertical face plate, the bar having an angular side serving to centralize the strip fabric within the slots such that the fabric is fed along a central line extending longitudinally through the fabric across the horizontal platen plate beneath the needle mechanism, the bar being also laterally adjustable and the slots being laterally adjustable for modifying or correcting the central feed line beneath the needle mechanism, the adjusting means including an adjustable nut having female threads matedly mounted on a threaded male projection extending through the biasing spring for controlling biasing pressure against the stretcher arm and additionally the regulating means including an extendable shaft means for shortening or lengthening the leverage by axial movement of the shaft, and as a part of the control of automatically moving the fabric across the plate in the centralized position at a proper rate of movement together with reduced variations in movement of the needle shaft, there is included between a driving cam rotatably mounted on an off-set portion of a driving cam and at an opposite end the mechanism reciprocally driving the toothed feed dog for advancing the fabric beneath the needle, is an adjustable shaft axially adjustable by regulation of a nut around the adjustable shaft, and the variations in needle reciprocation and depth of penetration being reduced by an adjustable pivot axis and by the lever pivoted on that axis being connected at its terminal end to a drive shaft which is centrally flexible and which at the terminal end connected with the pivoted lever mounted in a ball socket for free multi-directional movement and the other end of the flexible drive shaft being mounted for reciprocal axial movement on ball bearings around an off-set portion of a main rotatable drive shaft, undesirable variations in the reciprocating movement of finger and spreader hooks being reduced by replacing the meshing gears between a primary drive shaft and a secondary drive shaft with a belt having along its inner surface a plurality of treads meshable with corresponding teeth on each of the opposing toothed wheels on the respective shafts.

United States Patent 19 Medynski [451 July 17,1973

1 SEWING MACHINE Joseph Medynski, 18 Park St., Ramsey, N.J. 07446 [22] Filed: Aug. 12, 1971 [21] Appl. No.: 171,159

[76] Inventor:

[52] US. Cl. 112/152 [51] Int. Cl. D051! 35/06 [58] Field of Search 112/136, 152, 153,

[56] I v References Cited UNITED STATES PATENTS 57 ABSTRACT A sewing machine which in the preferred embodiment includes a hinged stretch bar regulatably biased for applying pressure against a fabric being fed through centralizing slots in a vertical face plate, the bar having an angular side serving to centralize the strip fabric within theslots such that the fabric is fed along a central line extending longitudinally through the fabric across the horizontal platen plate beneath the needle mechanism, the bar being also laterally adjustable and the slots being laterally adjustable for modifying or correcting the central feed line beneath the needle mechanism, the adjusting means including an adjustable nut having female threads matedly mounted on a threaded male projection extending through the biasing spring for controlling biasing pressure against the stretcher arm and additionally the regulating means including an extendable shaft means for shortening or lengthening the leverage by axial movement of the shaft, and as a part of the control of automatically moving the fabric across the plate in the centralized position at a proper rate of movement together with reduced variations in movement of the needle shaft, there is included between a driving cam rotatably mounted on an off-set portion of a driving cam and at an opposite end the mechanism reciprocally driving the toothed feed dog for advancing the fabric beneath the needle, is an adjustable shaft axially adjustable by regulation of a nut around the adjustable shaft, and the variations in needle reciprocation and depth of penetration being reduced by an adjustable pivot axis and by the lever pivoted on that axis being connected at'its terminal end to a drive shaft which is centrally flexible and which at the terminal end connected with the pivoted lever mounted in a ball socket for free multi-directional movement and the other end of the flexible drive shaft being mounted for reciprocal axial movement on ball bearings around an off-set portion of a main rotatable drive shaft, undesir-' able variations in the reciprocating movement of finger and spreader hooks being reduced by replacing the meshing gears between a primary drive shaft and a secondary drive shaft with a belt having along its inner surface a plurality of treads meshable with corresponding teeth on each of the opposing toothed wheels on the respeetive shafts.

7 Claims, 11 Drawing Figures mzmmm 1 3.745.949

SHEU 2 OF 2 INVENTOR. JOSEPH MEDYNSKI ATTORNEYS.

SEWING MACHINE This invention relates to a sewing machine of the general type descirbed in U. S. Pat. No. 2,958,301 issued Nov. 1, 1960, this invention relating to improvements in the invention of that patent which is hereby incorporated by reference.

BACKGROUND In the sewing machine described in the aforementioned patent, although the machine of that patent has many advantages in its simplicity of structure and operation as compared to other known sewing machines, it embodies certain features which although advantageous desirably could be improved upon. One such feature is the stretching mechanism for centering a piece of fabric such as a tie being fed toward and across the platen-plate beneath the needle-sewing position. Desirably the tension bar preferably would be more adjustable in the amount of tension and in its centering action. Similarly, the centering slots within the plate desirably would have some means for individualizing the feed mechanism to a particular fabric being fed therethrough, the better to center it. Finger and spreader hooks relative to fabric crossing the plate preferably would include some mechanism for coordinating with the rate at which the fabric is advanced and with the needle operation and the stretching. Preferably, also, the tensioning arm pressure is adjustable and regu1atable. Also preferably the stroke of the needle in relation to the rate and degree of advancing of the fabric across the platen-plate is regulatable and adjustable. Also, a new and alternative connection between the lever activating the actuation arm and the off-set drive shaft avoids the past problem of wear which in final result made the needle stroke inconsistent and unpredictable unless the parts were periodically replaced. Preferably also there might be an improvement in the gearing whereby after extended use the wear in the gearing would not be accompanied by the usual loss of timing in the movement of the hooks. Also preferably the loss of timing in the hooks mechanism as a result of lack of lubrication may be improved by an improved mechanism.

SUMMARY OF THE INVENTION Objects of the invention include the overcoming of difficulties and the gaining of advantages of the type discussed above. Other objects become apparent from the preceding and following disclosure.

One or more of the above objects are obtained by the invention as described hereafter.

The present invention is directed to a new sewing machine combination of substantially improved quality and regularity of stitching, being of the same basic operation and structure as the above-noted patent except as hereafter noted. The broad invention is directed to a combination of several basic interrelated coordinated improvements in the sewing machine of the abovenoted U.S. Pat. No. 2,958,301 dated Nov. 1, 1961 which was above-incorporated by reference, the present improved machine obviously being the same in parts and operation as shown in detail in that patent except for the novel and advantageous improvements obtaining the above-noted objects. The overall singular function to which all of these improvements are directed and to which they each contribute is the advantageous obtaining of a more uniform and properly guided stitch irrespective of the particular fabric, as an immediate and long-term result of consistent predictable and adjustable precisely-timed coordinated action of the needle action, the hooks and claws stroke, and the stretching arm, all of which are driven by a common drive mechanism typified by the drive wheel which is the connecting link so to speak between the needle leverage mechanism and the hooks and claws fabric-advancing mechanism, each of which by the improved stretcher mechanism are more controllably coordinateable and regulateable each to the stretcher mechanism by the improved control and regulateability of the stretcher mechanism by the sewing machine operator. As contrasted to the prior machine by which the tensioning guide was less successful and less predictable and less adjustable in positioning and pressure-applying, the improved stretcher mechanism has a different structural shape and several means for regulating the pressure of the actuating levers and for centering the fabric for making the pressure on the fabric and the claws and hooks action on the fabric more uniform and predictable. The needle action, as compared to the prior machine lower-lever actuationarm (rigid) being connected to the drive-wheel shaft by a spherical bearing at its bottom and prior upper actuation-arm end being connected by a. ball-bearing mounting to the needle arms intermediate pivoted pumping arm, for the present invention has the ball-bearing connection eccentrically mounted on the drive shaft with the rigid arm having a mid-point force-transmitting metallic strip bendable in a lateral plane to avoid strain on the ball-bearing connection, with the upper end of the rigid arm being pivotably connected by use of a ball joint to prevent the possibility of unwanted torques which priviously brought about wear and distorted the needle stroke, thereby maintining the precision timing of the needle stroke; also the intermediate pumping arm transmitting the pumping or reciprocating action to the needle arm is adjustable to further regulate pressure and perfect timing and to allow for wear by the intermediate arm being mounted on an adjustable eccentric pivot screw-controlled shaft. These improvements make the stitch more consistent and predictable with regard to the specific nature and pressure and centering of and by the novel stretcher componentof the new improved combination which by their interrelated ac- .tions make possible the obtaining of the objects of this invention. The hooks and claws stroke of the prior noted-patented machine was not adjustable in-the length of the stroke and also timing became altered by wear and distorting pressures of both the revolvable gears meshing between the drive shaft and the shaft driving the claws and the revolving non-adjustable clawsstroke-arm; in contrast the present invention presents a combination of elements machine which avoids significant wear in the connection between the stroke shaft and the drive shaft by eliminating the meshing of the pinion-gears and instead inserting a precise firm flexible'toothed belt (inner ridges), operable on the respective toothed wheels on the respective drive shaft and the stroke shaft, and by making the stroke arm adjustable to regulate claw stroke and allow for wear, and by an included wicking-lubrication mechanism, these several interrelated improvements preventing and/or providing for the correction of timing in order to maintain consistent and predictable stitching.

Thus, the drive wheel shaft drives the novel toothed belt which drives the stroke shaft which in turn drives the adjustable-length arm which in turn drives the reciprocatable claws, the drive-wheel shaft drives the eccentrically mounted ball-bearing mounted lower end of the needle-stroke actuation-arm having its flexible middle portion and having its upper end connected by the ball-joint to and drivable of the intermediate pumpingaction arm which at the opposite end thereof drives the needle arm in its reciprocating motion; also, in operator-controlled precision regulation, the spring biased and regulatable-pressure and regulatable-centering stretcher arm serves to perfect the desired stitching.

It should be noted that, although there are several modifications and substitutions of structures and mechanisms in the sewing machine of this invention as compared to that described in the aforementioned patent, each of the alterations are interrelated with one another in the obtaining of a more uniform stitch and guidance of that stitch for any particular fabric being sewed at a given time as well as for the sewing of fabrics over an extended period of time during which period normally wear and tear of machines of the type discussed above of the prior type would alter the precise interrelated functions. In particular, the invention includes an improved centralizing stretcher arm and forward vertical plate against which the stretcher arm functions adjustable in the leverage of the arm, the tension on the arm, and in lateral movement of the arm adjustably to alter the point of its centering action. Coordinated with this stretcher arm is a through-slit in the vertical forward plate, with upper and lower notches centrally of the through-slit. Also an adjustable part of the tension and leverage, is adjustable by an actuation lever adjustable in the length of the lever and in the degree of biasing of a spring pressing the actuatable arm against the lever by a nut screwed onto the shaft extending from the front plate, on the shaft end, with the lever extending to a leverage arm which arm is actuated by a chain connected to an adjustable shaft slidably adjustable through an aperture in which the shaft is lockable by a locking screw. Also as a part of coordinated hooks movement, the stroke of the hooks may be adjusted by a regulatable nut on a shaft member where regulation of the nut lengthens or shortens the stroke of the shaft. Also as an improvement preventing the stroke from varying over a period of time as a result of wearing gears,the actual meshing of gears is avoided by the employment of a timing belt connecting two toothed wheels, the inner face of the belt having laterally extending ridges corresponding to the spaces between the teeth of the toothed wheels; because of the precise fit, wear on this belt and on the toothed wheels is minimal and timing does not significantly vary over extended periods of time and wear. Also as a means of long term lubrication of the hooks mechanism, an oil is contained in the base of the sewing machine and is wicked to the various parts needing lubrication by a wick leading to and wrapped around the various parts to provide continuous and long term lubrication, thereby avoiding excessive wear and loss of coordinated interrelated claw movement relative to needle movement and the centering straightening action of the stretcher.

The needle arm of this and the former sewing machine is reciprocated in motion and in upward and downard paths by a lever arm pivoted around an intermediate axis. In order to better align the connection between the lever arm and the reciprocatable needle arm as well as to make slight adjustments in the height and- /or depth of reciprocation of the needle arm, the intermediate pivoting axis is eccentrically mounted with the portion of the axis mounted on the structure of the sewing machine being rotatable for adjustment to different positions by the loosening and tightening thereafter of one or more lockscrews. At the actuation end of this pumping lever the prior sewing machine of the above referred to patent included an actuation arm connected by a ball bearing-shaft which was subject to extreme wear as a result of the stress placed on the connecting point because of the arced movement of the actuation end of the pivoted lever as opposed to the lower end of the actuation arm being mounted around an eccentric mounting powered by a main drive shaft such that the arced movement wore out the upper end, i.e., ball bearing-shaft as well as the spherical bearing of the lower eccentric mounting. In the present invention, the upper end of the actuation arm permits pivotable movement by the employment of a ball joint but even though the upper end is movable in the direction of the arc movement, the lower end of the actuation arm does not become twisted because of an inventive intermediate connecting resilient strip, connecting the upper and lower half such that the upper half may bend laterally relative to the lower half. By virtue of this reduced stress upon the connecting ends of the actuation arm for actuation of the pivotable lever reciprocatable of the needle arm, the overall timing of the needle action as driven by the main drive shaft is maintained and predictable as compared to the tensioning and feeding action of the claws and hooks indirectly driven by the same main drive shaft. As a result of the coordinated multiple novel improvements of this invention, unitary improved operation of the coordinated action between the needle, hooks, stretching arm and the feeding claws is obtained.

THE FIGURES FIG. 1 illustrates a perspective side view of the sewing machine of this invention, the portions illustrated in solid lines representing the improvements such as the vertical plate with lateral adjustment means, the slots therein, the stretcher arm with its spring-adjustable actuation lever, which in turn is actuatable by the chain and slidable hook illustrated in part on the rearward side of the machine.

FIG. 1A illustrates a partial view of adjustable guides.

FIG. 2 is a view taken along line 22 of FIG. 1 illustrating a side view of a secondary drive shaft having eccentrically mounted thereon a rotatable annular arm with an extendable shaft of the invention for adjusting the position of the reciprocating claws.

FIG. 3 is a view taken along line 3-3 of FIG. 2 illustrating a top view of the extendable shaft as well as a top view of the wicking wick for lubricating the parts of the sewing machine.

FIG. 4 is a view taken along the line 4-4 of FIG. 1, illustrating a partial frontal view of the plate and the stretcher arm, more fully illustrating the upper and lower notches extending from the groove into which the stretcher arm is biased.

FIG. 5 illustrates a partial view of FIG. 4 along line 55.

FIG. 6 illustrates a view-in-part as taken along line 6-6 of FIG. 1.

FIG. 7 illustrates a view along line 7-7 of FIG. 6.

FIG. 8 illustrates a view taken along lines 8-8 of FIG. 6.

FIG. 9 illustrates a view taken along line 9-9 of FIG. 1.

FIG. illustrates a view along line 10-10 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION The oneness of improved stitching is arrived at by the regulatability of pressure of stretch and improved centering to perfect stretch which intimately effects precision and predictability of the action of the claws and straightness and positioning of a stitch by the needle arm, these being commonly known matters of the art, the improvements being achieved as set-forth above.

In particular, the drive wheel 37 (FIG. 6) and the eccentric ball-bearing-mounted wheel 36 are fixedly mounted on drive shaft 25, the eccentric wheel 25 driving the reciprocably mounted bend-arm 34a/34 with the flexible sheet 35 which through a ball-socket 33 pumps arm 28a on an adjustable eccentric mount 30 to act on conventional link 29 to reciprocate the needle arm, while in precision timing the drive shaft 25 drives wheel 24 and by belt 23 the wheel 26 drives stroke shaft 27 and thereby drives the eccentrically mounted shaft 19 and its wheel 18 which adjustably reciprocates arm 16 which in turn reciprocates the claw a, for example. The improved lubrication wicks 21, 21a, and 21b serve to maintain precision timing by avoiding wear and sticking and the like. In coordinated regulatable centering and tensioning stretching action, chain 38 actuates and controls the stretcher bar 3 against the spring 7 counter-action.

FIGS. 1 and 10 illustrate the stretcher mechanism including a vertical plate 1 having a horizontal slot 2 extending across the upper portion thereof and a horizontal flat biasing lever arm 3 mounted for pivotable movement by anchoring Iockscriws 4 onto arm 5 at hinge 6 base. The arm 5 is connected through biasing spring 7 to threaded plate shaft 8 by adjustable nut 9. The vertical plate 1 has notches 10 and 11 extending from the mid-portions of the slot 2, the lower slot 11 being viewable in FIG. 4. The centering action of the stretcher arm 3 with its slots 10 and 11 is coordinated with the slots 12 and 13 in their respective centering action, as the case may be -depending upon which of the two is being used. Beneath platen plate 14 are cooresponding centering members 12a and 130 which are adjustable to correct the centering action of slots 12 and 13 re spectively. The member 120 is adjustably movable forwardly and rearwardly while the member 13 is adjustably movable laterally to the right or left, and includes centering slot 14a. The advancing action of the fabric beneath the needle is brought about by the claws 15a and 15b on opposite sides of the needle arm, solely 15a, being viewablein FIG. 1.

FIG. 2 illustrates a view taken along line 2-2 of FIG. I of the extendable shaft 16 extendable by virtue of nut 17 around shaft 16 screwed into the eccentrically mounted annular structure 18 around rotating shaft 19 by virtue of extending the shaft 16 by rotation of the nut 17, the member 20 indirectly adjusts the forward to rearward rotating position of the claws 15a and 15b. Lubrication of the several parts of this mechanism are brought about by the wick 21a and 21b, for example, which are positioned to wick oil 22 from an oil basin 23.

FIG. 3 illustrates a view taken along line 3-3 of FIG. 2, as a top view thereof.

FIG. 4 illustrates a view taken along line 4-4 of FIG. 1 and represents a partial front view of the plate 1, the slot 2, the stretcher arm 3, the pivoting arm 5, the screw 4, and the notches 10 and 11.

FIG. 5 illustrates a view in part taken along line 5-5 of FIG. 4, representing a top view thereof.

FIG. 6 illustrates a view taken along line 6-6 of FIG. 1, and in particular illustrates a frontal view of a timing belt 2'3 mounted around toothed wheels 24 on the main drive shaft 25 and toothed wheel 26 mounted around shaft 27, the shaft 25 driving wheel 24 and the wheel 26 driving shaft 27.

FIG. 8 illustrates a side view of the toothed wheel 24, the laterally ridged timing belt 23 having ridges on the inner face of the belt, and the wheel 26.

FIGS. 1 and 6 also illustrate lever arm 28 connected at one end to the upwardly and downwardly reciprocal needle arm by way of an interconnecting link 29, the eccentric axis 30, the end 30a thereof being rotatable and adjustable by set screws 31, and the actuation end of the lever 28 being mounted by a ball 32 and a ball socket 33 of actuation member 34 connected to a lower portion 34a by a resilient plate 35 allowing the upper portion 34 to bend angularly relative to the lower portion 34a, in response to the reciprocating up and down. movement of the actuation end 28a of lever 28 the lower portion 34a being mounted with cylindrical ball bearings within the annular portion 34b. The annular portion 34b is mounted around an eccentric mounting 36 attached to the shaft 25 and to the main drive wheel 37.

FIG. 9 illustrates a view taken along line 9-9 of FIG. 1 and represents a rear view of the sewing machine shown in part, illustrating in particular the chain 38 of FIG. 1 and the slidably adjustable hook 39 slidable through an aperture the member 40 having a lockscrew 41, whereby the length of the lever has connected through the chain 38 to a foot pedal may be easily adjusted. The hook 39 and additional hook 42 hooked into the reciprocatable lever 43 controls the actuation of the stretch bar 3 by the lever shaft 8a attached to the lever 43 by the key 44, the lever 43 being biased against a spring 45. Y v

FIG. 10 illustrates a view taken along line 10-10 of FIG. 9 illustrating a side cross sectional view of plate 1, lever extending through the plate I, in order to exert pressure against the arm 4 biased by spring 7 against the nut 9 on shaft 8.

FIG. 1A illustrates the mechanism by which the rearward plate 12 and the forward plate 13 are each adjustable for coordinating the bearing action and movement of fabric advanced by reciprocating action of the claws 15a and 15b.

It is within the scope of this invention to make use of obvious equivalents and to make modifications apparent to a person skilled in this art.

I claim: I

l. A sewing machine comprising in combination: a substantially upright plate having :a substantially horizontal through-slit extending across an upper portion of the plate; a spring-biased angular-bar of elongated shape pivotably mounted relative to the plate, said bar having an end offset toward said plate and a central portion that is substantially concave toward said plate and a biasing spring biasing the bar toward the plate such that the bar is movable toward and away from the plate and fits into said slit, the longitudinal angular side of the bar being slidable into the slit such that the offset end portions of the angular side are first to enter said slit and such that the central portion of the angular side is last to move into the slit; an actuation means attached to said angular bar for acting in opposition to the biased position of said bar such as to be movable of said bar in a direction out-of and away-from said slit when actuated; and a sewing machine means for receiving material over said upright plate and between the biased bar and said upright plate such that the central portion of the biased side of said bar serves to center the feed of fabric centrally of a platen-plate of the sewing machine.

2. A sewing machine according to claim 1, in which said actuation means includes an adjustable lever means for extending and shortening the range of bar movement for said annular bar.

3. A sewing machine according to claim 2, in which about centrally located between opposite ends of said slit and adjacent to said slit, said plate includes each of an upper through-notch and a lower through-notch opposing one-another on opposite edges of the slit in juxtaposition to said bar central portion.

4. A sewing machine according to claim 3, in which said spring-biased angular-bar includes an adjustable spring means for applying variable pressure against said bar toward said slit.

5. A sewing machine according to claim 4, in which said upright plate is laterally adjustable in each of opposite directions to and from which said slit extends, including through-slots through which anchor screws are inserted and adjustable of pressure against said plate optionally preventing and permitting said lateral adjusting.

6. A sewing machine according to claim 5, in which said adjustable lever means includes a chain, an extendable hook attached to the chain, a pivoted lever having a handle means attached to an opposite end of said hook means; and said actuation means including a push-pull sleeved longitudinally-slidable cable lever ad- 10 justably attached to said handle at one end of said slidable lever and attachedto said plate at an opposite end of said slidable lever.

7. A sewing machine according to claim 1, in which said sewing machine means includes a flat-faced platen-plate having a first substantially inverted-V fabriccentering guide through-slot with one leg of the V-slot extending through the forward edge of said platen-plate and a shorter additional plate-guide through-slot leg more centrally located, each platen-plate through-slot having a base portion substantially parallel with said forward edge, and includes an additional at least twopart adjustably mounted guide-plate means mounted beneath said platen-plate in a plane substantially parallel to said platen-plates plane, said additional guideplate means including a first part and a second part spaced from one another and shaped such that a second substantially inverted V-slot is formed substantially corresponding to and beneath said first V-slot, said first plate part defining an outer periphery of said second V-slot and said second plate part defining an inner periphery of said second V-slot, said first plate part being slidably adjustable toward and away from said forward edge of said bed-plate, said second plate part being slidable sidewardly and adjustable in each of opposite directions substantially parallel with said forward edge. t k 

1. A sewing machine comprising in combination: a substantially upright plate having a substantially horizontal through-slit extending across an upper portion of the plate; a spring-biased angular-bar of elongated shape pivotably mounted relative to the plate, said bar having an end offset toward said plate and a central portion that is substantially concave toward said plate and a biasing spring biasing the bar toward the plate such that the bar is movable toward and away from the plate and fits into said slit, the longitudinal angular side of the bar being slidable into the slit such that the offset end portions of the angular side are first to enter said slit and such that the central portion of the angular side is last to move into the slit; an actuation means attached to said angular bar for acting in opposition to the biased position of said bar such as to be movable of said bar in a direction out-of and away-from said slit when actuated; and a sewing machine means for receiving material over said upright plate and between the biased bar and said upright plate such that the central portion of the biased side of said bar serves to center the feed of fabric centrally of a platen-plate of the sewing machine.
 2. A sewing machine according to claim 1, in which said actuation means includes an adjustable lever means for extending and shortening the range of bar movement for said annular bar.
 3. A sewing machine according to claim 2, in which about centrally located between opposite ends of said slit and adjacent to said slit, said plate includes each of an upper through-notch and a lower through-notch opposing one-another on opposite edges of the slit in juxtaposition to said bar central portion.
 4. A sewing machine according to claim 3, in which said spring-biased angular-bar includes an adjustable spring means for applying variable pressure against said bar toward said slit.
 5. A sewing machine according to claim 4, in which said upright plate is laterally adjustable in each of opposite directions to and from which said slit extends, including through-slots through which anchor screws are inserted and adjustable of pressure against said plate optionally preventing and permitting said lateral adjusting.
 6. A sewing machine according to claim 5, in which said adjustable lever means includes a chain, an extendable hook attached to the chain, a pivoted lever having a handle means attached to an opposite end of said hook means; and said actuation means including a push-pull sleeved longitudinally-slidable cable lever adjustably attached to said handle at one end of said slidable lever and attached to said plate at an opposite end of said slidable lever.
 7. A sewing machine according to claim 1, in which said sewing machine means includes a flat-faced platen-plate having a first substantially inverted-V fabric-centering guide through-slot with one leg of the V-slot extending through the forward edge of said platen-plate and a shorter additional plate-guide through-slot leg more centrally located, each platen-plate through-slot having a base portion substantially parallel with said forward edge, and includes an additional at least two-part adjustably mounted guide-plate means mounted beneath said platen-plate in a plane substantially parallel to said platen-plate''s plane, said additional guide-plate means including a first part and a second part spaced from one another and shaped such that a second substantially inverted V-slot is formed substantially corresponding to and beneath said first V-slot, said first plate part defining an outer periphery of said second V-slot and said second plate part defining an inner periphery of said second V-slot, said first plate part being slidably adjustable toward and away from said forward edge of said bed-plate, said second plate part being slidable sidewardly and adjustable in each of opposite directions substantially parallel with said forward edge. 